This add-on is not compatible with your version of Firefox because of the following:

AddThis for Firefox is the best add-on to make sharing and bookmarking simple. Have all your favorite web 2.0 social networking, bookmarking, blogging, and e-mail services at your fingertips. Share any page, anytime, with anyone.

This add-on is not compatible with your version of Firefox because of the following:

http://en.wikipedia.org/wiki/Text-to-voice. TTS gives Firefox the power of speech. Select text, click the button on the bottom right of Firefox window and this add-on speaks the selected text for you. Isn't it brilliant? Audio is downloadable.

This add-on is not compatible with your version of Firefox because of the following:

Downloads YouTube videos in all available formats (FLV, MP4, WebM, and 3GP) with video quality of your choice. It also contains a pure JavaScript library to extract the ORIGINAL audio file embedded in video files.

This add-on is not compatible with your version of Firefox because of the following:

Keep track of how much time you spend on the web, and where you spend it. A toolbar ticker shows the time spent at the current site or the total time spent on the web today. A summary page sums up data for the past 70 days, 10 weeks, and 6 months.